help jeep barely moving

hey guys my dad just bought a 96 grand cherokee 4wd,automatic 4.0 motor and 2 daz later when u put in gear its seems to spin the rpm`s raise but doesnt shift into 2nd,now also when he bought it the vic(vehicle info center) was flashing and by the time he got home was completely blank and had burnt up,but he still drove it for 2 daz like that,well on my way home to take out the vic.....it stated the shifting problem,my question is.......does the truck need the vic to run and shift correctly or is it another problem all together? i dont mind replacing the vic as i have already taken it out,but dont want to buy another if the tranny is bad also? trans fluid is red and doesnt smell bad to me,and when u first start up it runs and shifts fine then after a few minutes it starts slippin? p.s ive tried it in 4wd low,high and 2wd drive they all work but it still slips in any of them,ive tried to include how its acting but if u need more info to help just ask,any clues or directions to head are appreciated thnx bb